Cerebral Relaxation Times from Postmortem MR Imaging of Adults

Purpose: We measured T-1 and T-2 values of cerebral postmortem magnetic resonance (PMMR) imaging and compared the data of cadavers with that of living human subjects. Materials and Methods: We performed PMMR imaging of the brains of 30 adults (22 men, 8 women; mean age, 58.2 years) whose deaths were for reasons other than brain injury or disease at a mean of 29.4 hours after death. Before imaging, the bodies were kept in cold storage at 4 degrees C (mean rectal temperature, 15.6 degrees C). We measured T-1 and T-2 values in the brain bilaterally at 5 sites (bilateral caudate nucleus, putamen, thalamus and gray matter and white matter of the frontal lobe) and compared the data of PMMR imaging with that from MR imaging of the corresponding sites in 24 healthy volunteers (9 men, 15 women; mean age, 51.8 years). We also investigated the influence of body temperature on T-1 and T-2 values. Results: Compared with MR imaging findings in the living subjects, PMMR imaging showed significantly shorter T-1 values in the caudate nucleus, putamen, thalamus and gray matter and white matter of the frontal lobe and significantly longer T-2 values in the gray matter and white matter of the frontal lobe; T-2 values in the caudate nucleus, putamen, and thalamus showed no such differences. T-1 values correlated significantly with body temperature in all 5 brain sites measured, but T-2 values did not. Conclusion: Compared with findings of cerebral MR imaging in living adult subjects, those of PMMR imaging tended to demonstrate shorter T-1 values and longer T-2 values. We attribute this to increased water content of tissue, reduced pH, and reduced body temperature after death.